How come...diesel engine building related.

[Bob Holmes]

How come I never see any articles, in diesel performance magazines, that explain head porting, or cam dynamics?

With Big Red approaching 400,000 miles, I need to start thinking about a rebuild or replacement bullet for the old guy (no this thread really isn't about that so hold your suggestions on engine replacements). I started reading the diesel magazines to try and get a sense of how to properly go about that endeavour. After reading the magazines for over a year, I haven't seen any of the basic engine dynamics explained. I'd really like to know what special cam needs a diesel has. How about a basic porting article (although I assume that porting is porting.?)

Diesel magazines seem to be about lifted trucks with mega turbo combos. Thats my basic impression. If someone knows of a decent primer on cam selection for diesel power, I'd like that information.

Thanks.

[Barry Donovan]

I wondered these things a long time, my dads rigs.
if no reasearch by a company on their own, not many know what in heck made what it is..

if it is not a 550 from cat, the 550 someone crammed is not the same.
on gas engines..it is just the opposite. they end up the same. Now today there is computers in the trickery.

I was interested too. today they got it so even the catalysts could be a helper and not a performance hit. diesels use the whole realm front to back...and whoever built it.

a thing too with diesels, they are the biggets engines in relation to power. not screaming ninny wheelies down a track, I mean power. I concentrated on cats after my dads last crazy cummins ona short wheel base cabover (torture for people, even the trailers and loads got tortured). unlike cars, little bodies and big diesel is insane. give it the big rails for the big engine.. all kinds of opposites to hot rodding to think of. more steel versus less. Chuckle if you want.. I treat the little 3 main boxers like that. go big on engine, add more steel. it is not within itself...it wants to put out. Diesels torque based are a much larger version of that same think...they don't just pass around hot rod parts. staying proprietary for safety.

thinking of the cat driven rigs.. the longer the wheelbase, most often has the bigger engine. The real big ones have a large space for a third axle, hence they look lon g.some get it, some don't. Custom long trucks look huge for that reason.

[Brian Lohnes]

Bob, you and I are on the same wave length. From reading Diesel Power and a couple others, it seems that the "scene" is largely about adding turbochargers until you blow it to smithereens and then having someone assemble you a long block so you can do it again. Lots of truck features but not a lot of engine building tech.

[Brian Lohnes]

Bob, just hit this link and order youself a $9,500 compacted graphite powerstroke block. No sweat!

http://www.gohypermax.com/

[Bob Holmes]

Geee, thanks for all the help Brian...

Its frustrating. My experience with turbo engines leads me to think you can use the same induction theories, but cam timing must be different. And you have to add the additional issue of fuel timing.

Maybe there is a "how to Hot Rod diesel engines" book.

[TheSilverBuick]

I'm going way out on a limb I'm not qualified to walk on, but perhaps most cam and porting improvements ultimately increase the upper RPM band of an engine, where as with Diesels, without pretty advanced injectors are still rpm limited? And for any of the potential lower rpm gains from porting and cam work are easily crutched with more boost that is much easier to do? At least to the limits of the hard parts? Just my theory on it.

[Scott Liggett]

This article looked interesting.

http://www.enginebuildermag.com/Article/81065/diesel_performance_camshafts_lifters_and_valvetrain.aspx

[TC]

Diesels meter the fuel not the air going into the motor add more fuel get more power........And when adding more fuel doesn't get you the power you want that is when a bigger turbo comes into play....... This is the reason those programmers get 100+hp increases without touching the inside of the motor......

[Huskinhano]

Interesting post. I remember reading a few years ago about Gale Banks. He was talking about shifting the power band in diesels to be more in line with gas engines. This way drive trains could be made lighter. IIRC Audi was/is experimenting with diesels in F1 and were having problems exactly what Banks was talking about. With all the torque the diesel was making, keeping the transaxle together a problem. So this has me wondering when the OEMs are going to apply modern gas engine designs to diesel. Why not 4V DOHC heads that cam timing can be varied? You could advance the cams at load speed to kill low end torque and retard them to increase upper end torque. Maybe get gas like power curve with diesel efficiency.

[SuperBuickGuy]

you can have 1500 hp in a stock-appearing diesel; why bother with porting, cams, or anything else? Heck with a programmer you can have 1000 lb torque out of any of the diesels made by the big 3

that said, I would guess there are websites dedicated to powerstroke diesels. For the 6.2 there's a couple, there I learned that there are better blocks (the later, the better), that you can raise compression with off-the shelf pistons, and that it's pointless to use anything but a stock cam (turbo or not)... I would suppose that would be on the PS sites as well?

but, if you're like me, here's where I got all bothered - I'm going to spend how many thousands of dollars on a STOCK rebuild? surely I can hop it up for that kind of money.... the answer is, nope for the 6.2/6.5 family...

[TC]

you can have 1500 hp in a stock-appearing diesel; why bother with porting, cams, or anything else? Heck with a programmer you can have 1000 lb torque out of any of the diesels made by the big 3

that said, I would guess there are websites dedicated to powerstroke diesels. For the 6.2 there's a couple, there I learned that there are better blocks (the later, the better), that you can raise compression with off-the shelf pistons, and that it's pointless to use anything but a stock cam (turbo or not)... I would suppose that would be on the PS sites as well?

but, if you're like me, here's where I got all bothered - I'm going to spend how many thousands of dollars on a STOCK rebuild? surely I can hop it up for that kind of money.... the answer is, nope for the 6.2/6.5 family...

That's what I'm saying, why bother, hell my duramax with the stock 360hp and 650ft-lbs of torque blows away 80% of the cars on the street and that is in a 7000lb truck........ I can get a programmer to take it up to about 500hp and 900ft-lbs of torque, so why bother messing with the inners.......

Also did you know that most diesels don't have throttle bodies.........

[BOSSMAN]

You don't see much info cause the motors are so horribly detuned from the factory. The bolt on and programmer stuff just amazes me how easy it is to gain power on diesels. I have a big shop close to me that specializes in Performance Diesel Trucks so I need to pay a visit and introduce myself. The downside is how heavy those heads are. Not sure if I want to venture in that territory just yet. I will say the majority of the porting effort is on the exhaust side. All other theory should be similar.

[Beagle]

the guys building 5000 rpm diesels probably aren't reading Diesel Power all that much? That's the only reason I can think to change the cam, is to move the power band up which most street guys don't want I'm betting... otherwise, it'd be about more cylinder pressure and that's the turbo and injectors job? Everything I read is tuner, injector, turbo... like HRM's Head Cam Intake stories. Why port when you can buy new?

just throwing a WAG out there Bob. The trade rags rarely spend any quality time on gasoline engine porting either. 8" exhaust tips and 38's "look" cool and sell a lot. Tuners can really wake one up or melt one down. There's no 500 hp 100.00 cam like is claimed for some cars, but there are lots of 600 hp turbos!

fwiw, I did a search for grins and at 525.00 you don't want to "ooops" on your cam!

Stage 1 Cam: - $525.00
This is the cam International should have put in this engine for the Powerstroke truck application. This cam is a perfect stock replacement cam that has performance and towing benefits by lowering smoke output and EGTs. With a slightly different centerline and lobe aggressiveness over stock, this cam does everything the stock cam does only better under all conditions. This cam also prevents reversion with high drive pressures common to typical single street turbo setups. Stock heads with upgraded valve springs are the minimum requirement (Comp Cams 910 shimmed to 125lbs on the seat), but lightly ported heads really complement this cam. No piston modifications are required and valve lift with stock rockers is .450” Upgraded pushrods are required because of the added spring pressure.

I can check on ... say Comp Cams reputation easy enough, but who are these guys?

http://www.gearheadautomotiveperformance.com/index.php?page=products_73_cams

Could be great, could be crap. For 500 clams, I'd kinda like to know first. Does Steve Brule keep a dyno cell open for them?

Wait - I have an idea.. get Ed Curtis and Jay Allen to discuss diesel cams. That should be entertaining.

BeeCam FTW!
(all hail BeeCam)

[DanStokes]

The guys tree'd me on this one. Mild porting does pay off, especially for less modified fuel/boost applications but most owners don't go that far when they already have transmission-destroying power with bolt-ons. As a Diesel racer I know that even almost stock my issue is safeguarding the driveline - in the case of a Dodge automatic it's the trans. So no reason for cams, porting, etc.

Remember, it's not a good plan to mess with the combustion chamber area of the head as that has the "firing mechanism" built into it. Mexican hat, modified Mexican hat, and the Benz pre-chamber designs (Google 'em) are all either in the piston crown and/or head and can be easily messed up without a highly skilled technician doing the work. Like to the point that the mixture won't fire or won't fire properly. So working with bolt-ons gets the job done.

As far as cam design - I'm not sure. Seems like a little tweeking would help but I really don't have any info.

Dan

[Beagle]

By comparison, when was the last time you saw a Car Craft showing you intricate details on not FuBarring a short side radius? Generally glossed over "leave it to the pro's" ... the article you see is "how to port match" and then next month in the tech column, "Port matching is worthless unless you do some bowl work too"... maybe that's an extreme take on it, but that's kind of what I see most of the time.


Dulcich admits porting iron SUCKS and almost all of the rags say "Buy new aluminum, done" ... probably doesn't hurt any that New Aluminum happens to be an advertiser. (Cough... Cough)


How are you supposed to get Pro if you always "leave it to the pro's" ???

What is it they say, Wisdom is the result of correctly finding all the wrong ways to do something?


Lemme try another way -

Hey BOSSMAN, Gimme all your secrets, okay?


Hahaha. Just foolin around. I hear you Bob. They put what sells advertiser parts in the articles. Nobody in their right mind ports cast iron any more... lol. I blew up about 100.00 in carbide bits and probably got lung cancer not "leaving it to the pro's" and the sad thing is, I won't even know if it worked because I didn't get before and after flow number, or before and after HP numbers.

We were talking about flow benches one time and I can't remember the name of the gauge?

V = k (h/D)0.5

errr. I want fries with that.